The plasma potential measured by cylindrical and planar Langmuir probes has been shown to differ from the plasma potential measured by emissive probes in the neighborhood of the presheath near a negatively biased electrode immersed in a weakly collisional low temperature argon plasma. There are two principal results demonstrated in this paper. First, while it is well known that Langmuir probes cannot reliably measure plasma potentials inside of sheaths, results presented here demonstrate that the problem persists in presheaths, the quasineutral plasma bordering sheaths. It is known that emissive probes analyzed in the limit of zero emission accurately measure the plasma potential in the sheath. It is now clear that they are the only known electrostatic probe technique able to measure the plasma potential accurately throughout the presheath. Second, it is shown that the difference between potential measurements made by Langmuir probes and emissive probes in the body of the plasma, farther than a presheath distance from the boundary, is not proportional to Te as has been previously claimed.

中文翻译：

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Langmuir Probes 和 Emissive Probes 在预护套中测量的等离子体电位差异的实验研究

已显示由圆柱形和平面朗缪尔探针测量的等离子体电位不同于在预鞘附近浸没在弱碰撞低温氩等离子体中的负偏压电极附近的发射探针测量的等离子体电位。本文展示了两个主要结果。首先，虽然众所周知，朗缪尔探针不能可靠地测量鞘内的等离子体电位，但这里提供的结果表明，问题仍然存在于预鞘中，即准中性等离子体边界鞘中。众所周知，在零发射极限下分析的发射探针可准确测量鞘层中的等离子体电位。现在很明显，它们是唯一已知的能够准确测量整个预鞘中的等离子体电位的静电探针技术。第二，